title: Prevalence and epidemiology of microbial pathogens causing bloodstream infections: results of the OASIS multicenter study.
abstract: Beginning on April 2007, a prospective multicenter study was performed to investigate prevalence and epidemiology of microbial pathogens causing bloodstream infections (BSIs). Twenty microbiology laboratories participated to the survey over a 1-year period. A total of 11,638 episodes of BSI occurred in 11 202 patients, with 8.5% (n=985) of episodes being polymicrobial. Of 12 781 causative organisms, aerobic Gram-negative bacteria were 47.4% (n=6058), whereas Gram-positives accounted for 43.9% (n=5608). The remaining organisms included fungal species (n=924, 7.2%) and anaerobes (n=191, 1.5%). The most prevalent agents were Escherichia coli (21.7%), Staphylococcus aureus (14.9%), Staphylococcus epidermidis (8.2%), Pseudomonas aeruginosa (7.0%), and Enterococcus faecalis (6.3%). Isolates recovered from patients admitted to medical, surgical, and intensive care units accounted for 62.9%, 17.7%, and 19.4% of cases, respectively. BSIs were classified as hospital-acquired in 67.2% of cases. Compared with previous studies, our data show an increasing role of Gram-negative bacteria among both hospital- and community-acquired blood isolates.
authors.affiliation: Laboratory of Microbiology, Ospedale Alessandro Manzoni, Via dell'Eremo, 9/11, 23900, Lecco, Italy. f.luzzaro@ospedale.lecco.it
authors.forename: Francesco
authors.initials: F
authors.lastname: Luzzaro
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Ortisi
authors.forename: Monica
authors.initials: M
authors.lastname: Larosa
authors.forename: Monica
authors.initials: M
authors.lastname: Drago
authors.forename: Gioconda
authors.initials: G
authors.lastname: Brigante
authors.forename: Giovanni
authors.initials: G
authors.lastname: Gesu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016470:Bacteremia / Q000453:epidemiology / Q000382:microbiology*; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000382:microbiology; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology; D005260:Female; D006090:Gram-Negative Bacteria / Q000145:classification / Q000302:isolation & purification*; D006094:Gram-Positive Bacteria / Q000145:classification / Q000302:isolation & purification*; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies